A high-end jewelry and watch store in the Design District is alleging Miami-based construction company Moderna Development nearly tripled the negotiated price for interior work done to a two-story commercial building owned by well-heeled real estate investor Sam Herzberg. And when the job was finished, Moderna claimed it was still owed an additional $21,966, according to a recent lawsuit filed in Miami-Dade Circuit Court.

Exclusividades Vagu Corp. sued Moderna in June for unjust enrichment and filing a fraudulent lien for the allegedly unpaid work. The lawsuit alleges Moderna willfully exaggerated its claim and prepared it with gross negligence. Herzberg is not a party to the lawsuit.

Attorneys for Exclusividades Vagu did not respond to requests for comment. Gary Kovacs, the lawyer for Moderna, said his client is trying to resolve the dispute with Exclusividades Vagu. According to Miami-Dade court records, Kovacs recently requested an extension of time to respond to the lawsuit.

“We certainly deny the allegations,” Kovacs said. “And we will vigorously defend them if necessary.”

According to the lawsuit, Moderna provided Exclusividades Vagu with an initial proposal in the amount of $160,182 on Oct. 17 of last year. Both sides agreed and signed a contract to begin the work at the store at 3818 Northeast Second Avenue in the Miami Design District.

However, the total price ended up at $442,344 after Moderna charged for certain materials and services that neither party mutually agreed to and which never reached the tenant’s premises, the lawsuit states. In April, Moderna filed a lien against Exclusividades Vagu for the $21,996.

Exclusividades Vagu, which is owned by Marian and Fernando Valero, wants an accounting of Moderna’s books in order to determine the exact amount of charges and invoices billed by the construction company.

The jewelry store sells luxury brands such as De Grisogono, Jacob & Co, Roger Dubuis, and Baume et Mercier, among others and specializes in the sale of high-quality, 18-karat-gold, diamond, pearl and semiprecious stones, bracelets, earrings, necklaces, pendants, and watches.

According to Miami-Dade property records, Herzberg’s company 3800 Design District LLC purchased the property for $11.4 million in 2015. The Miami Beach-based real estate mogul also owns the Sterling Building at 927 Lincoln Road and 901 Lincoln Road, home to Victoria’s Secret, in Miami Beach.